package cn.tedu.sp06.fallback;

import cn.tedu.web.util.JsonResult;
import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * 通过zuul 网关，调用后台商品服务失败时，
 * 会执行这段降级代码，向客户端返回降级结果
 */
@Component
public class ItemFB implements FallbackProvider {
    //设置当前降级类，是针对哪个服务的降级类
    // - item-service: 只针对商品服务降级
    // - * : 星号=针对所有服务应用当前降级类
    // - null: 和*相同
    @Override
    public String getRoute() {
        return "item-service";
    }

    //发送给客户端的降级结果，封装再response对象中
    @Override
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {

        return new ClientHttpResponse() {
            //封装状态码，如200=ok
            @Override
            public HttpStatus getStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR; // {code:500,text:"服务器内部错误"}
            }

            @Override
            public int getRawStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.value(); // 500
            }

            @Override
            public String getStatusText() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.getReasonPhrase(); // "服务器内部错误"
            }

            @Override
            public void close() {
                //用来关闭流
                //BAIS不需要关
            }

            @Override
            public InputStream getBody() throws IOException {
                //JsonResult {code:500,msg:"调用商品服务失败",data:null}
                String json=JsonResult.err().code(500).msg("调用商品服务失败").toString();

                return new ByteArrayInputStream(json.getBytes("UTF-8"));
            }

            @Override
            public HttpHeaders getHeaders() {
                // Content-Type: application/json;charset=UTF-8
                HttpHeaders h=new HttpHeaders();
                h.add("Content-Type", "application/json;charset=UTF-8");
                return h;
            }
        };
    }
}
